libpdbg: Add ocmb hwunit
libpdbg: Add ocmb hwunit

Signed-off-by: Amitay Isaacs <a505e7c038746dbeb3edcd8d146dbd515432801f@ozlabs.org>
Reviewed-by: Joel Stanley <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@jms.id.au>

open-power/pdbg,open-power/pdbg,open-power/pdbg